Organic chemicals of wide variety and increasing complexity are daily entering the biosphere, and they are doing so at unprecedented rates. Populations in the developed countries have reaped the benefits of a wide range of chemical products, but pollution and the necessity to efficiently, and effectively detoxify the chemical waste presents severe technological problems. Organic pollutants from diverse agricultural, municipal and industrial facilities, and waste sites partition preferentially into the soil, water or air phases and spread rapidly throughout the environment. Many of these materials, even in small concentrations, adversely affect life forms, and create serious environmental threats. Toxicity, carcinogenicity, and mutagenicity are the most critical biological properties of a potential pollutant, a very large number of organics of which have been identified by the U.S. Environmental Protection Agency as particularly threatening. For example, the widespread use over the last few decades of herbicides, pesticides and related high risk chemicals, e.g., organochlorines, polychlorobiphenyls (PCB's) and chlorinated phenols, have resulted in serious environmental problems.
Enzymes have been proposed as possibly useful in the treatment of toxic wastes of this type. Enzymes are biocatalytic materials known to possess extraordinary high efficiency, and enzymes of one type or another can be used to catalyze almost any chemical reaction without producing harmful substances. The successful use of enzymes to biotransform and biodegrade these toxic materials into harmless substances, however, has met with limited success. This is largely due to their failure to biodegrade these materials within an acceptable time frame. Also, a given enzyme can catalyze only a single reaction. The mineralization of most known toxic compounds however requires a complex multi-step series of reactions which must be carried out with the aid of a biochemical contactor, which in turn must be continuously regenerated by a cell (or continuously added to the reaction mixture).
Recently issued U.S. Pat. Nos. 4,775,650 and 4,882,066 disclose contact materials for the detoxification of streams containing toxic chemicals. The '650 and '066 patents disclose the use of porous solids on the surfaces of which thin films of chitinous material are dispersed. These materials, on contact with a stream containing, e.g., a toxic halogenated organic compound, at appropriate conditions, complex with and remove the toxic organic compounds from solution. In U.S. Pat. No. 4,859,594 there is disclosed a biocatalytic composition wherein microorganisms are immobilized and attached to porous solid supports. These biocatalysts, on contact at appropriate conditions with a solution containing a toxic halogenated organic compound produce reaction and degradation of the halogenated organic compound component to detoxify the solution. Whereas the contact materials described by these several patents, particularly the biocatalysts described in the '594 patent, have proven admirably effective in detoxifying liquids containing toxic halogenated organic compounds, there nonetheless remains a need for improving the performance of processes utilizing these, and other materials for use in the decontamination and detoxification of toxic streams of these types. There also exists a need for reactors of improved design for carrying out these reactions due to the volatility of many of the chemical toxicants targeted for detoxification biodegradation.